1. Field of the Invention
The invention relates to the field of sail-boats.
More specifically, the invention relates to the rigging of sail-boats and especially spinnakers.
Spinnakers are well known in the field of sailing and are used to increase the sail surface area of boats in order to increase their speed under certain wind directions. Spinnakers take the shape of a light, very hollow triangular sail with a very large area. There are thus many shapes of spinnaker. Known spinnakers notably include radial, tri-radial and asymmetrical spinnakers. Radial and tri-radial spinnakers have a symmetrical shape along the longitudinal axis while asymmetrical spinnakers have a shape without a longitudinal axis of symmetry.
Spinnakers are generally made out of a very light synthetic fabric that enables them to:
be easily rigged,
be easily filled with wind,
occupy a relatively small volume when they are stowed.
Their domed shape when they are filled with wind furthermore enables them to pull the boat very efficiently.
Spinnakers are used essentially in downwind or quarterwind sailing conditions, but experienced helmsmen are capable of using them under less favorable wind directions.
However, it is relatively difficult to handle spinnakers. Indeed, their great surface area and shape prevents them being unfurled when the sail-boat is still. They can only be sent up when the boat is on the move.
Furthermore, the size of their surface area makes them unusable in heavy weather. Their large surface area indeed may prove to be dangerous in a strong gale.
The spinnaker therefore can only be used when weather conditions permit it. In this case, it is unfurled in front of the sail-boat with its halyard point being fixed to a spinnaker halyard brought to the end of the mast, with its tack being kept away solely by the force of the wind that sweeps into it in fixing it to a boom (which may also be used for a Genoa-sail) fixed to the front mast of the sail-boat, and by tautening its free end by means of a sheet.
One of the problems raised by spinnakers lies in their flimsiness. Indeed, they are made of a light and relatively flimsy material as compared with other sails and can therefore easily get torn in a gale.
Another problem inherent in sails of this type lies in the fact that they can easily get wound around the stay, especially in light weather during a failed maneuver or when the helmsman lets down a little too much and takes the wind out of the spinnaker with the main-sail. A stay such as this is formed by a cable designed to stiffen the mast in the frontward direction in an essentially longitudinal direction. This type of cable, which may be tensioned by means of a rigging device, is also used as a support either for the jib or possibly for a Genoa-sail. Thus, when the spinnaker is wound about this stay, it is relatively difficult to release it. For this, speedy action is needed before the cloth of the spinnaker gets torn in chafing against the stay. At the same time, care has to be taken not to luff or jibe in placing the spanker-boom manually over the false position and holding it in this position until the turns of the spinnaker get unwound by themselves. If such an operation proves to be fruitless, then a crew member must be sent to the top of the mast to unhook the halyard from the spinnaker and climb down along the stay, undoing the turns as he goes along. If despite such an operation, the spinnaker cannot be unfurled, then it must be decided to cut it with a knife.
Yet another problem raised by spinnakers lies in the fact that they have to be lowered as soon as weather conditions change and that, to do this, a crew member has to be sent to the front of the boat. Once the spinnaker has been hauled down, it has to be folded and stowed in a bag except when it has to be brought out again when conditions permit it. It will therefore be understood that the maneuvering of a spinnaker with a small crew or a single crew member is not easy.
2. Description of the Prior Art
In order to resolve this problem, there already exists a prior art device taking the form of a tube slightly flared out at its lower end and designed to be mounted in a sliding manner on the spinnaker so as to cap it in order to spill when it is lowered and release it so that it can be unfurled when it is raised. Such a device, known as a "spinnaker tube", is provided in its upper part with an out-haul strap enabling the tube to be raised to uncover the spinnaker and in its lower part with an in-haul strap to lower the tube and spill the spinnaker. A tube such as this has a strop made of cable inside which the spinnaker is fixed, the halyard of the spinnaker for its part being secured to the upper end of the tube by means of a pulley receiving the out-haul strap.
A device such as this has the drawback of being incapable of being handled from the cockpit of the sail-boat and of requiring the presence of a crew member at the bows of the sail-boat to handle the in-haul and out-haul straps respectively to spill and unfurl the spinnaker.
Another drawback raised by spinnaker tubes results from the fact that they may get blocked when the tube is in a raised position and prevent the spilling of the spinnaker.
Yet another drawback inherent in such tubes lies in the fact that it is impossible for them to give the spinnaker to which they are a fixed a variable wind-exposed surface area.
There also exist known devices in the prior art designed to enable the furling of the jib or Genoa and various devices that enable the main sail to be wound on the mast or on the boom.
When there is no furling device, the halyard point of the jib (or Genoa-sail) is fixed to the halyard having the same name. The hoist of the jib, which has a bolt rope that strengthens it, is then secured throughout its length (from the tack to the halyard point) to the stay connecting the bows of the sail-boat to the mast and the jib is unfurled as and when the jib is fixed to the stay. Once the jib is completely unfurled, the jib halyard is frapped to the foot of the mast and the jib sheet is hauled taut depending on the force and direction of the wind.
The presence of a furling device makes it possible to avoid having to haul down the jib when it no longer has to be used by furling it around the stay. Conventionally, a furling device such as this takes the form of a tube designed to be positioned rotationally about this stay and having a length substantially equal to the height of the jib and having one or more longitudinal grooves in which the bolt rope of the jib may be made to slide, or other types of elements for hooking the jib. A furling device such as this furthermore has a furling drum with one end controlling the furling of the jib about the tube arranged about the stay. The use of a furling device such as this is as follows. When the jib is positioned on the furling device, the jib halyard is brought to the mast so as to be secured to the halyard point of the jib. The hoist of the jib is then inserted into the groove or grooves of the tube of the furling device and the jib is unfurled. Once the jib is in position, the jib halyard is frapped to the foot of the mast and the jib is wound about the tube of the furling device. When it is desired to send up the jib, all that needs to be done is to haul the jib sheet taut, this causing the unfurling of the sail and the winding of the end about the drum of the furling device. When it is desired to reduce the windward surface area of the jib or completely furl it, the end secured to the drum has to be drawn after having slackened the jib sheet.
Furling devices such as this, which may also be used to furl a Genoa-sail, avert the need to haul down this type of sail and make it possible to send it up very swiftly. However, they cannot be used except for sails having an entire side, namely the hoist, fixed to the stay.
There also exist furling devices in the prior art designed to be fixed to the mast of sail-boats and enable the furling of the main sail. These furling devices have a profile that matches the mast. Within these furling devices there is placed a furling tube operated by an end emerging at the foot of the mast. Devices such as this furthermore have a slider that matches the spanker-boom, on which there slides a pulley designed to be secured to the sheet point of the main-sail. When such a furling device is used, the main-sail may be furled within the profile fixed to the mast by action on the emerging end at the foot of the mast. When the main-sail has to be sent up, it suffices to make the main-sail slide on the slider of the spanker-boom.
All these furling devices may be motor-driven. There also exist furling devices that can be used to furl the main-sail on the spanker-boom.
The main-sail furling devices may be attached to the mast or the spanker-boom or may form an integral part thereof.
Just like the jib and/or Genoa-sail furling device, the main-sail furling devices can be used only for sails (main sails, storm sails) whose hoist is secured essentially throughout its height to the furling tube.
An aim of the invention is to provide a system that enables the furling of a spinnaker.
Another aim of the invention is to provide a system such as this enabling the positioning of the spinnaker on a boom, from the cockpit of the sail-boat.
Yet another aim of the invention is to propose a system such as this that makes it possible to free the foredeck of the boat, namely to avoid encumbering it with the folded boom or spinnaker.
Finally, another aim of the invention is to provide a system such as this enabling the partial deployment of the spinnaker depending on the force of the wind.